Bogota, March 23 (IANS): Colombia's police director Rodolfo Palomino has confirmed that a bomb blast killed four people, and injured 14 others outside a shelter for the homeless and drug rehabilitation centre of the country's northeastern Medellin city.

Palomino condemned the attack, in which six policemen were among the inured, and offered a reward of 20 million Colombian pesos ($10,000) to anyone who provides information leading to the capture of those responsible for the attack, Xinhua reported, citing Colombia's Caracol Radio network.

Deputy Mayor of Medellin, Luis Fernando Suarez reported that a homeless man was carrying the explosives in a bag that was activated by cellphone.

"It exploded at the door and he died in that place, (while the) other three died in hospitals in Medellin and also left six policemen injured and others wounded," Suarez said.

uarez said the attack was directed against the actions carried out by the Mayor's office and the Metropolitan Police of Medellin to crack down on the use of drugs among homeless people.

The official claimed those behind the attack were drug dealers who opposed the new programme for the homeless who were consuming drugs to receive medical and psychological treatment at the centre, among other benefits.

The mayor's office of Medellin stepped up the programme two months ago.